Development of a copper containing 690 MPa yield strength quenched and tempered steel

摘要: Demands placed on modern steels mean that higher strengths are being sought while alloy contents, particularly carbon, decreased. These two conflicting requirements have forced steel designers to consider micro-alloying, heat treatment and precipitation strengthening meet market demands. This study concentrated the use of hardening by copper maintain strength reduced quenched tempered steels. Many studies proportions above 1 % in as rolled It was intent this examine effect levels between 0 development a low 690 MPa yield structural steel. The changes hardness upon tempering, tensile testing, Charpy v-notch impact Jominy hardenability, bead-on-plate weld testing optical microscopy were used evaluate Also covered empirical descriptions response treatment. Both free containing analysis. In studying steels, observed 0.4% (nominal composition). shown fracture toughness targets military commercial specifications can be met developed. As result based hardening, hardenability tests showed much than would predicted basis carbon content volume fraction martensite produced function cooling rate. demonstrated weldability assessed bead plate test, is superior currently alloys. Therefore, aim maintaining increasing reducing clearly achieved.